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Web Shield is currently the most sophisticated security component of Avast Antivirus, and monitors all network activities. Web shield may slightly affect the speed of your internet activity, due to its high functionality, but the difference is generally imperceptible.

Internet speed tests may be affected while scanning for connection speed if Web Shield is enabled, as the test can confuse Web Shield activity speed with internet speed and local hardware.

Why is my high speed connection slower with Web Shield on?

High speed connections greater than 20Mbits/s may see noticeable delays under certain conditions while Web Shield is enabled. For example, if a hard drive has an I/O speed of 30Mbits/s, the Web Shield can decrease the loading speed of a webpage because the hard drive I/O operations are doubled during active scans. In this case, the internet input of 20Mbits/s combined with 20Mbits/s of Web scanner data output then exceeds the maximum hard drive ability and can lead to noticeable delays.

Are there specific devices that have compatibility issues with Web Shield?

Some network components or connection types may be incompatible with a parts of Avast Antivirus or Web Shield in particular, as the default setting for some routers and ADSL modems may expect a different connection or packet type. This mismatch can cause connection resets and timeouts. Web Shield scans may also cause a device to time out if the device has a short timeout setting.

Avast monitors reports regarding specific devices and contacts device vendors about frequent issues with proposed coding solutions or workarounds. However, many issues are related to specific settings within Web Shield and can be disabled without eliminating your protection.

Are there any workarounds to improve web performance when using Web Shield?

You can customize your Web Shield configuration or if absolutely necessary, disable some settings as workarounds for the web speed issue. These features can be disabled with only a minor impact on user security.

In Main settings: Untick the box next to Use intelligent stream scanning to disable the setting. When enabled, intelligent stream scan continuously scans files while they are being downloaded. When disabled, it may increase your browsing speed, as downloaded files are scanned only after download . However, in rare cases unticking the box can slow down web browsing even more.

In Main settings: Untick the box next to Enable HTTPS scanning to disable the setting. When enabled, the HTTPS scan protects your system against the malware delivered over HTTPS connections. When disabled, File Shield still scans all downloaded content before running any files.

In Sensitivity: Set the Heuristic sensitivity bars to Off and untick Use code emulation to disable the settings. When enabled, Heuristics consume your PC resources to continuously analyze code for malware. When disabled, Web shield will consume fewer resources on your PC and speed up your web browsing, but may not detect malicious code.